Pressure intensifier system



April 26, 1955 E. M. GREER 2,706,891

PRESSURE INTENSIFIER SYSTEM Filed May 51, 1952 INVENTOR Edward Greer BYU flan/6 ##(naaa ATTORNEYS United States Patent PRESSURE INTENSIFIERSYSTEM Edward M. Greer, Great Neck, N. Y., assignor to Greer Hydraulics,Inc., a corporation of New York Application May 31, 1952, Serial No.291,015

2 Claims. (CI. 60-52) It is among the objects of the invention toprovide a hydraulic circuit which will furnish a relatively low pressurefrom a low pressure source to bring the movable member of ahydraulically operated unit to one position, and will provide arelatively high pressure from such low pressure source to move saidmovable member to a second position, which circuit is relatively simpleand not likely to become deranged and in which both the low pressure andhigh pressure from such low pressure source may readily be controlled.

This application is a continuation-in-part of copending applicationSerial No. 678,533 filed June 22, 1946, now abandoned.

In the accompanying drawing in which is shown one or more of variouspossible embodiments of the several features of the invention, thesingle figure is a circuit diagram of the equipment.

Referring now to the drawing, the system desirably comprises a reservoir11 connected by line 12 to the inlet 13 of a fluid pump 14 desirablydriven by a motor 15, a filter 16 and a control valve 17 being connectedin line 12. The output 18 of the pump 14 is connected by line 19 to theinput 21 of an unloader valve 22, desirably of the type put out byVickers, Inc. The valve 22 desirably has a bore 23 therein incommunication with inlet 21, and the outlet 24 of valve 22 is also incommunication with said bore 23.

The bore 23 desirably has a plug 25 afiixed in its open end, said plughaving a bore 26 therethrough with its outlet 27 connected by line 28 toa return line 29 which is connected to reservoir 11. Slidably mounted inthe bore 23 of valve 22 is a piston 31 having an axial stem 32 rigidtherewith defining a valve head at its end adapted to seat in the innerend 33 of bore 26 to seal the latter, a coil spring 34 compressedbetween the end 35 of bore 23 and the piston 31 normally retaining saidvalve head 30 on its seat.

The piston 31 desirably has a bore 37 therethrough providingcommunication between the chambers 38 and 39 on each side of piston 31respectively. Chamber 39 desirably has a passageway 41 leadingthereinto, which has its outlet end 42 leading into a cavity 43 in saidvalve. Outlet 42 normally is closed by a ball 44 retained on its seat bya coil spring 45 compressed between the ball and a plug 46, which has abore therethrough connected by line 47 to the inlet 13 of pump 14. Thechamber 39 has a second passageway 51 leading thereinto, the outlet endof which is connected to port 52 of variable pressure relief valve 53.

The valve 53 desirably comprises a cylindrical casing 54 having a port55 in one end thereof connected by line 56 to the inlet 58 of a standardpressure accumulator 59, and through valve 57 by line 61 to feed line62. Slidably mounted in cylinder 54 is a piston 65 which desirably is ofreduced diameter at its mid-portion as at 66. The length of said reduceddiameter portion 66 is such that when the piston is moved in cylinder 54against the tension of coil spring 67, which is compressed between theend of the piston and an adjustment plug 69 screwed in the threaded endof the cylinder, communication will be afforded between ports 52 and 71in said cylinder, the latter port being connected by line 72 to returnline 29.

The outlet port 24 of valve 22 to which feed line 62 is connected, has acheck valve 75 therein which permits How of fluid only from the port 24through the line 62; The line 62 which has a pressure guage See 77connected thereto, is connected by line 78 to inlet port 79 of rotaryvalve 81, and by line 82 to inlet port 83 of rotary valve 84. Inaddition to port 79, valve 81 has three additional ports, 80, 85 and 86,said ports being spaced degrees apart. The valve 81 has a rotary member87 with passageway 88 and 89 therethrough, which in one position of therotary member 87 will connect ports 79 and 86, and ports 80 and 85, andin the second position of the rotary member will connect ports 79 and 80and ports 85 and 86.

The port 86 of valve 81 is connected by line 91 to port 92 of a secondvariable pressure relief valve 93, which is substantially identical tovalve 53, and desirably has a cylindrical casing 94 in which a piston 95is Slidably mounted. The piston 95 is of desirably reduced diameter atits mid-portion as at 96, defining ends 97 and 98, the latter being ofgreater diameter than the former. The length of said reduced portion 96is such that when the piston 95 is moved in cylinder 94 against thetension of coil spring 99 compressed between the end 98 of the piston 95and a plug 101 screwed in the end of the cylinder, communication will beafiorded between port 92 and a port 102 in cylinder 94. The port 102 isdesirably connected by line 104 to return line 29 and by line 105 toport 85 of valve 81. The cylinder 94 has a third port 106 which isconnected by line 107 to a port 108 in a pressure booster unit 109. Thebooster unit 109 desirably comprises a cylinder 111 in which a piston112 having an axial piston rod 113 of reduced diameter is 'slidablymounted, the free end of said piston extending through an opening 114 inthe end 115 of the cylinder. The area of the end 116 of piston 112 inchamber 117 of cylinder 111 to the left of piston 112 is greater thanthe area of the end 118 of piston 112 in chamber 119 of cylinder 111 tothe right of the piston.

The cylinder 111 has a second port 121 in communication with the chamber119 and connected by line 122 to a junction 123 to which a pressureguage 124 is connected. Also connected at one end to junction 123 is aline 125, the other end of which is connected to port 80 of valve 81.Desirably, a check valve 126 is connected in line to permit How of fluidfrom port 80 to the junction 123. In addition, a line 127 is connectedat one end to junction 123 and at its other end to the inlet 128 of acheck valve 129, and also by line 131 to the port 132 of a hydraulicunit, illustratively a press 133. As shown, the line 127 has a checkvalve 134 therein to permit fiow of fluid from the junction 123 to theport 132.

The valve 129 desirably comprises a casing 135 having a bore 136therethrough. Slidably mounted in said bore is a valve head 137 normallyurged toward its seat 138 by a coil spring 139. The valve head 137desirably has a stem 141, the inner end 142 of which is engaged by a cam143 afiixed to a shaft 144. The cam 143 which is controlled by a handle145 is so designed that in one position in which its high portionengages end 142 it will retain the valve head 137 away from its seat 138and in another position it will permit the spring 139 to seat the valvehead.

The valve 84, in addition to port 83 has three additional ports, 146,147 and 148, said ports being spaced 90 degrees apart. The valve 84 hasa rotary member 149 with passageways 151 and 152 therein which are ofenlarged dimensions at their ends 153. The passageways 151 and 152 areso spaced that in one position of the rotary member 149, the ports 146and 147 and ports 83 and 148 are connected, and in a second position ofsaid rotary member 149, the ports 147 and 148, and ports 83 and 146 areconnected.

The outlet 156 of valve 129 is desirably connected by line 157 to port146 of valve 84. The port 147 of said valve is connected by line 158 toreturn line 29. The port 148 of said valve is connected by line 159 toport 161 of hydraulic press 133, the ports 132 and 161 of said pressbeing positioned on opposite sides of the piston 162 therein to whichthe plunger 163 of the press is connected.

Means are provided simultaneously to actuate the valves 81, 84 and 124.To this end, a bar 165 is connected at one end to a handle 166 pivotallyconnected to the rotatable member 149 of valve 84. The other end of bar165 desirably has a lost motion slot 167 therein, and a handle 168connected to the rotatable member 87 of valve 81 is connected in saidslot. A lever 169 pivotally mounted as at 171 has one end pivotallyconnected in slot 172 in handle 145. The lever 169 is pivotallyconnected to bar 165 as at 173 and has a handle 174 for actuationthereof.

Operation Assuming that the plunger 163 of the hydraulic press 133 is inthe down position, having completed the application of high pressure tothe work, the system is operated to lift such plunger.

To this end, the handle 174 is moved to the position shown in whichports 79 and 86 and ports 80 and 85 of valve 81 are in communication;ports 83 and 148, and ports 146 and 147 of valve 84 are in communicationand the valve 129 is in open position, the cam 143 reacting againstvalve stem 141 to retain valve head 137 off its seat 138.

The motor 15 is energized so that pump 14 will suck fluid from reservoir11, through open valve 17 and line 12, through filter 16 to the inlet 13of pump 14. From the outlet 18 of said pump 14, the fluid will flowthrough line 19 into inlet port 21 of unloader valve 22. Fluid will thenflow into bore 23 of valve 22 and thence out of outlet 24 through checkvalve 75, feed line 62, line 61, open valve 57 into the inlet 58 ofpressure accumulator 59 to charge the latter.

Fluid under pressure will also flow through line 56 to the port 55 ofrelief valve 53 to react against the piston 65 therein. However, as thetension of spring 67 has been set so that a force caused by a pressureof say 1000 p. s. i. or more is required to move the piston, no movementwill be imparted thereto as the pressure on the line is initially below1000 p. s. i.

Fluid will also flow through lines 62 and 78, port 79, passageway 88,port 86, line 91, port 92 of relief valve 93, through such valve, port106 thereof, line 107 into inlet 108 of booster unit 109. As the pistonrod 113 in cylinder 111 of booster unit 109 has already been moved toits extreme position to the right, no further movement will be impartedthereto and the flow of liquid in line 107 will be stopped. The fluidunder pressure from the pump will also flow through line 62 intopressure gauge 77 so that the pressure in such line will be indicated.In addition, the fluid will flow from line 62, through line 82, intoport 83 of valve 84, through passageway 152, port 148, line 159 intoport 161 of hydraulic press 133.

As the result of the application of the fluid under pressure to thepress 133 beneath the piston 162 thereof, the latter will be raised tolift the plunger 163 away from the work. Such upward movement of piston162 will force the fluid thereabove through line 131 into inlet 128 ofvalve 124, the check valve 134 preventing flow of fluid through line127. As valve 129 is open, the fluid from line 131 will passtherethrough and through line 157 into port 146 of valve 84 and thencethrough passageway 151 in said valve 84, through port 147, line 158 andreturn line 29 back to the reservoir 11.

When the piston 162 reaches the limit of its upward movement, the flowof fluid in line 159 will stop. Due to the stoppage of fiow in lines 107and 159, the pressure in line 62 will build up and the accumulator 59will continue to charge. As such gradually increasing pressure isapplied through line 56 to port 55 of valve 53, when the pressure risesabove 1000 p. s. i., the tension of spring 67 will be overcome andpiston 65 will move to provide communication between ports 52 and 71.Consequently, fluid will flow from chamber 39 of valve 22 throu hpassageway 51, ports 52 and 71, line 72, to return line 29 back toreservoir 11. As a result, the pressure in chamber 39 would drop and theforce exerted in chamber 38 of valve 22 against piston 31, of greaterthan 1000 p. s. i. would move piston 31 to the right against the slighttension of coil spring 34 so that valve head will move off its seat 33.Consequently, the fluid under a pressure of greater than 1000 p. s. i.would discharge out of outlet 27 of valve 22 into reservoir 11, therebydropping the pressure on the main feed line 62 to 1000 p. s. i., atwhich time by reason of the drop in pressure in line 56, the piston 65would move to cut off communication between ports 52 and 71 so that thepressure in chamber 39 of valve 22 would again build up to seatwalvehead 30. 7

With the construction above described the pressure applied to pistons112 and 162 will not rise above l000 p. s. i. and the chargedaccumulator 59 will maintain this pressure.

The next step in the sequence of operations is to position the workbeneath the plunger 163 and to move such plunger into engagement withsuch work while at the same time retracting the piston 112 and pistonrod 113 in booster cylinder 111. To this end the handle 174 of lever 169is moved to the left. As a result, the handle of valve 129 is rotated sothat the high point of the cam 143 is moved away from the end 142 ofvalve stem 141, the spring 139 thereupon moving the valve head 137 ontoits seat 138 to close the valve 129. This movement of handle 174 willmove bar to the left and the handles 168 and 166 of valves 81 and 84Will be moved to turn the rotatable members 87 and 149 of said valvesrespectively in a clockwise direction until ports 79 and 80 and ports 85and 86 of valve 81 are in communication and ports 83 and 146 and 147 and148 of valve 84 are in communication.

As a result of such setting of the valves 81, 84 and 129, the fluidunder pressure from the pump 14 forced into feed line 62, will passthrough line 78 into port 79 of valve 81, through passageway 88, port80, check valve 126, line 125, into junction 123. As a result, thepressure of the fluid applied to junction 123 will be indicated onpressure gauge 124. The fluid will flow from junction 123 through line122 into port 121 to react against the piston 112 to move the latter andpiston rod 113 to retracted position in booster cylinder 111. The fluidin chamber 117 of such cylinder will flow out of port 108, through line107 into port 106 of relief valve 93 and thence through such valve, port92, line 91, port 86, passageway 89, port 85, lines 105 and 104 toreturn line 29 and thence to the reservoir 11. As a result, the boosterwill be reset for the pressure stroke.

Fluid will also flow from junction 123 through line 127, check valve 134to the inlet 128 of valve 129. As such valve is closed, the fluid willflow through line 131 into port 132 of press 133, thereby forcing thepiston 162 and plunger 163 downwardly until the latter engages the work.The fluid beneath the piston 162 will flow out of port 161 through line159 into port 148 of valve 84 and thence through passageway 152, port147, line 158 to return line 29 and thence to reservoir 11.

Thus, as a result of the above operation, the booster will be re-set,ready for the power stroke and the plunger 163 of the press 133 will bebrought into engagement with the work.

When both the pistons 112 and 162 have reached the limit of theirstrokes, the pressure in line 62 will build up until a pressure of say1000 p. s. i. is attained. At such time the relief valve 53 willfunction as previously described to actuate unloader valve 22 so thatthe pressure will be retained at 1000 p. s. i.

The next step in the operation is to provide a high pressure on piston162 so that the plunger 163 will be moved with great force into contactwith the work.

For this purpose, the handle 174 is moved to the right. As a result ofthe lost motion slot in handle 145, valve 129 is retained in closedposition. By reason of the enlarged ends 153 of passageways 151 and 152,the ports 147, 148 and 83, 146 of valve 84 will remain connected and theports 79, 86 and 80, 85 of valve 81 will be connected. As a result ofthe setting of the valves 81, 84 and 129, the fluid under pressure infeed line 62 will flow through line 78, port 79, passageway 88, port 86,line 91, port 92 of valve 93, through such valve, port 106, line 107into port 108 of booster unit 109. As the pressure in line 107 is nowillustratively 1000 p. s. i. by reason of the charged pressureaccumulator 59, the force applied to the end 116 of piston 112 inbooster cylinder 111 will be equal to the product of the pressure andthe area of such end 116. Assuming that the area of end 116 is, say,seven times the area of the end 118 of piston 112, by the formula thepressure developed on the fluid in the chamber 119 of cylinder 106 tothe right of the piston will be seven times the applied pressure in thechamber 117 of the cylinder [11 to the left of the piston, i. e., 7000p. s. i. The fluid under such pressure of 7000 p. s. i. will flow fromport 121 through line 122, to junction 123, to be read on pressure gauge124. By reason of the check valve 126 in line 125 the fluid from line122 will flow through line 127, through check valve 134 to the inlet 128of valve 129. As such valve is in closed position, the fluid will flowthrough line 131 into port 132 of the press 133 to react against thepiston 162 therein, thereby moving the plunger 163 against the work witha force of 7000 p. s. i. The fluid beneath piston 162 will flow out ofport 161 through line 159, port 148, passageway 152, port 147, lines 158and 29 to the reservoir 11.

Although the fluid is under a pressure of 1000 p. s. i. in lines 62, 82,port 83 of valve 84, passageway 151, port 146, line 157 into theoutlet156 of valve 129, as such valve is in closed position and retained insuch position by the pressure of 7000 p. s. i. into inlet 122, the valvewill remain closed.

By reason of the relief valve 93, the force exerted on plunger 163 mayreadily be adjusted to an amount below that caused by a pressure of 7000p. s. i. Thus, the tension of spring 99 of valve 93 may be adjusted byturning plug 101 so that it requires a force produced by a pressure ofsay 900 p. s. i. against the piston 95 to effect movement thereof.Consequently as the pressure on the fluid in line 91 is 1000 p. s. i.,due to the charged pressure accumulator 59, by reason of the fact thatthe area of the end 98 of piston 95 is greater than that of end 97, thetension on spring 99 will be overcome and piston 95 will move to providecommunication between ports 92 and 102. As a result, fluid will flowfrom line 91, through ports 92 and 102, lines 104 and 29 to thereservoir 11 with resultant drop in the pressure in line 91 which willcause the piston 95 to move to cut off communication between ports 92and 102. Although the fluid under a pressure of say 1000 p. s. i. willalso flow from port 102 through line 105, port 85, passageway 89, port80, check valve 126 and line 125 to junction 123, as the pressure atsuch junction is much greater than 1000 p. s. i., the latter pressurewill have substantially no elfect.

It is apparent therefore that the pressure applied to port 108 ofbooster unit 109 may be varied at will to an amount below 1000 p. s. i.and consequently the pressure in line 122 will be reducedcorrespondingly from 7000 p. s. 1.

In the event that the booster piston 112 reaches the limit of its strokewith consequent reduction in the pressure applied to piston 162 of press133 before a sutficient time has elapsed for completion of the operationon the work, the valve 81 may be rotated to restore the piston 117 ofbooster 109 to its retracted position and the valve 81 can then beturned to again apply high pressure from port 121 to line 122.

With the equipment above described, it is possible with a source of lowpressure to provide an adjustable high pressure for actuating ahydraulic unit and the equipment permits utilization of the low pressureto set the press to its working position and to return it to standbyposition and the application of such high pressure when required for thework stroke.

As many changes could be made in the above construction, and manyapparently widely dilferent embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent of the United States is:

l. A hydraulic circuit comprising a fluid source, a pump connected tosaid fluid source, means to drive said pump, a feed line connected tothe outlet of said pump,

an unloader valve in said feed line, a pressure relief valve connectedto said feed line and controlling said unloader valve to actuate thelatter when the pressure in said feed line rises above a predeterminedamount, a pressure booster unit comprising a cylinder having a pistonslidably mounted therein with a piston rod affixed on one side thereof,the area of the piston on the piston rod side being smaller than thearea of the piston on the other side thereof, a second pressure reliefvalve comprising a cylindrical casing, a piston slidable in said casingand of reduced diameter at its mid portion defining a pair of enlargedends, one of said ends being of larger area than the other, a pair ofports in said casing, resilient means reacting against said piston tomaintain said ports out of communication, a line connecting said feedline to one of the ports in said second pressure relief valve, a lineconnecting the other of said ports of said return line, said casinghaving a third port normally in communication with said first port, aline connecting said third port to said booster cylinder on the side ofthe piston opposed to its piston rod, a hydraulic unit comprising acylinder having a piston slidably mounted therein, a line connected atone end to said booster cylinder on the piston rod side of the pistonand at its other end to said hydraulic cylinder on one side of thepiston therein, and a line connecting said hydraulic cylinder on theother side of the piston therein to said fluid source, whereby when thepressure of the fluid in the first port rises above a predeterminedamount, based on the setting of the resilient means reacting against thepiston of the second pressure relief valve, said piston will move toprovide communication between the first and second ports therebylowering the pressure applied to the piston in said booster cylinder.

2. A hydraulic circuit comprising a fluid source, a pump connected tosaid fluid source, means to drive said pump, a feed line connected tothe outlet of said pump, an unloader valve in said feed line, a pressurerelief valve connected to said feed line and controlling said unloadervalve to actuate the latter when the pressure in said feed line risesabove a predetermined amount, a pressure booster unit comprising acylinder having a piston slidably mounted therein with a piston rodaffixed on one side thereof, the area of the piston on the piston rodside being smaller than the area of the piston on the other sidethereof, a second pressure relief valve, a line connecting said feedline through said second pressure relief valve to said booster cylinderon the side of the piston opposed to the piston rod, a hydraulic unitcomprising a cylinder having a piston slidably mounted therein, a lineconnected at one end to said booster cylinder on the piston rod side ofits piston and at its other end to the hydraulic unit cylinder on oneside of the piston of the latter, a control valve and a two positionselector valve which in one position connects said feed line to saidhydraulic unit cylinder on the other side of its piston and connectssaid fluid source through said control valve to said hydraulic unitcylinder on said first-mentioned side of its piston and in its secondposition connects said hydraulic unit cylinder on said other side of itspiston to said fluid source and connects said feed line to the outlet ofsaid control valve.

References Cited in the file of this patent UNITED STATES PATENTS2,043,453 Vickers June 9, 1936 2,088,859 Huck Aug. 3, 1937 2,351,872Parker June 20, 1944 2,403,912 Doll July 16, 1946 2,562,764 Bowers July31, 1951 2,612,756 Peterson et al. Oct. 7, 1952

